When starting Seamonkey with at least 2 windows and 2 tabs in each window by using the option to restore the previous session, the menu entry to bookmark the group of tabs is greyed out from the second window onwards. (e.g. having 5 Windows, each containing several tabs, there are at least 4 windows which have this option greyed out.
When opening another window with new tabs, the option is available/enabled in that window. The "old" windows remain as they are.
Quitting SM by Ctrl+Q and restarting with that new window in addition to the old makes makes it behaving like the old ones of course.
Illustration of the issue in a localized Seamonkey 2.2 http://img718.imageshack.us/img718/1752/gruppetabslesezeichen.png
Hartmut Figge confirmed issue for SM2.5 Nighty in d.c.s.m.browser <4E4094CD.90009@hfigge.myfqdn.de>
steps to reproduce:
- use option to restore session in browser preferences as starting-page
- open more than one window with more than one tab in each window
- quit SM (e.g. by pressing Ctrl+Q) and restart
- try to bookmark group of tabs in any window except the first one
expected result:
- Bookmarking tab group is enabled as usual
actual result:
- Bookmarking tab group is disabled

FWIW, the command is Browser:BookmarkAllTabs (navigator.xul and/or navigatorOverlay.xul). From navigatorOverlay.xul:
<!-- The command is disabled for the hidden window. Otherwise its enabled
state is handled by gBookmarkAllTabsHandler. -->
<command id="Browser:BookmarkAllTabs"
label="&addCurTabsAsCmd.label;" accesskey="&addCurTabsAsCmd.accesskey;"
oncommand="gBookmarkAllTabsHandler.doCommand();"
disabled="true"/>
gBookmarkAllTabsHandler is defined in navigator.js, reacting to tabOpen and tabClose events (and setting the disabled attribute to false in case of a tabOpen event with current tab count == 2). I guess in the case of Session Restore, the event listeners are added too late so the events are not received/processed by gBookmarkAllTabsHandler and subsequently the disabled state of the menuitem is not changed.
Misak, Neil, what can we do about this? [I guess FF doesn't have a case for this; they don't have that menuitem in the menu anymore, only in tab context menus.]

Created attachment 552794[details][diff][review]
patch
I'll give this a try...
Note: The tabbrowser updating is already fine since the updatePopupMenu method takes care of disabling all tbattr=tabbrowser-multiple items if there is only one tab.

Created attachment 552796[details][diff][review]
patch v1a [Checkin: comments 10 and 13]
Bah, forgot the Bookmarks button menu (on the Personal Toolbar).
Note: Using any tab's context menu serves as a workaround until this bug gets fixed (of course that doesn't bring the shortcut back to life; one could bind a call to PlacesCommandHook.bookmarkCurrentPages() to a shortcut using KeyConfig, though.

Comment on attachment 552796[details][diff][review]
patch v1a [Checkin: comments 10 and 13]
I have this vague memory that KaiRo wanted the gBookmarkAllTabsHandler for compatibility with Firefox. And then they went and removed it...